Incorporation of urea-derived 13C into microbial communities in four different agriculture soils

The objective of this study was to investigate changes in the composition of the soil microbial community brought about by urea application and differences in the incorporation of urea-derived C into the soil phospholipid fatty acid (PLFA) pool at differing soil pH. We selected four soils which ranged in pH from 3.9 to 7.8. ¹³C-labeled urea was applied at two concentrations 100 and 200 mg N kg^?1 which represents commonly used and high levels of application. Significant hydrolysis of applied urea occurred within 2 h; less than 2 % of urea-C was retained in the soil with one exception, the fluvo-aquic soil at pH 7.8 amended with 200 mg kg^?1 urea-N 3 days after urea application. According to principal component analysis (PCA), the effect of urea and incubation time on microbial community composition was far weaker than differences between the four soils due to their large differences in basic properties; the scores of PC2 were significantly correlated with pH values. The incorporation of ¹³C-urea to PLFAs increased with soil pH; this may be related to increases in the speciation of inorganic C into bicarbonate.¹³C label was primarily incorporated into 16:1ω5c, 16:0, and cy19:0 in red soil, pH 3.9; and into 16:1ω7c, 16:0, and 16:1ω5c in fluvo-aquic soil, pH 7.8. A wider range of PLFAs became labeled in the two paddy soils at pH 5.2 and 6.7. This suggests that the profile of PLFAs labeled from the application of ¹³C-urea may be affected by redox potential.     

Attraction and antennal response of the common wasp,Vespula vulgaris (L.), to selected synthetic chemicals in New Zealand beech forests

BACKGROUND: The common wasp, Vespula vulgaris (L.), and the German wasp, Vespula germanica (F.), are significant problems in New Zealand beech forests (Nothofagus spp.), adversely affecting native birds and invertebrate biodiversity. This work was undertaken to develop synthetic attractants for these species to enable more efficient monitoring and management. RESULTS: Seven known wasp attractants (acetic acid, butyl butyrate, isobutanol, heptyl butyrate, octyl butyrate and 2,4‐hexadienyl butyrate) were field tested, and only heptyl butyrate and octyl butyrate attracted significantly higher numbers of wasps than a non‐baited trap. Accordingly, a series of straight‐chain esters from methyl to decyl butyrate were prepared and field tested for attraction of social wasps. Peak biological activity occurred with hexyl butyrate, heptyl butyrate, octyl butyrate and nonyl butyrate. Polyethylene bags emitting approximately 18.4–22.6 mg day^?1 of heptyl butyrate were more attractive than polyethylene bags emitting approximately 14.7–16.8 mg day^?1 of heptyl butyrate in the field. Electroantennogram (EAG) studies indicated that queens and workers of V. vulgaris had olfactory receptor neurons responding to various aliphatic butyrates. CONCLUSION: These results are the first to be reported on the EAG response and the attraction of social wasps to synthetic chemicals in New Zealand beech forests and will enable monitoring of social wasp activity in beech forests. Copyright © 2009 Society of Chemical Industry     

The rapid and accurate determination of germ tube emergence site by Blumeria graminis conidia

The development of appressoria by germinating Blumeria graminis conidia depends on its germ tubes making contact with the host surface. Low angle, low temperature scanning electron microscopy showed that 80% or more of first-formed germ tubes of f. spp. hordei, tritici and avenae conidia emerged from close to the host leaf surface, and so made contact with it allowing them to become functional primary germ tubes. Light microscopy of f. sp.hordei confirmed this result and, in addition, showed that germ tubes frequently emerged close to, and contacted, various hydrophobic and hydrophilic artificial substrata. Geometric models of conidium-substratum interfaces were developed and a “surface point method” was derived to predict the frequency with which contact would result if germ tube emergence was a random phenomenon. However, observed contact frequencies were far higher (c. three to eight times) than predicted. Thus, the germ tube emergence site was determined as a response to substratum contact. In part, this appeared to be a non-specific response. Nevertheless, germ tube contact frequencies were greater on the curved surface of leaf epidermal cells than on planar surface, suggesting that specific recognition of leaf surface characteristics may promote directional emergence. The area of contact required to stimulate directional germ tube emergence was very small: contact with a microneedle tip or with a spiders’ suspension thread was sufficient for many conidia. Similarly, on leaves, the only contact is between the tips of a limited number of conidial wall projections and the edges of epicuticular leaf wax plates. Micromanipulation to roll conidia so that their original site of contact with a leaf was rotated away from it, led to the majority of first-formed germ tubes growing away from the leaf, i.e. emerging close to the site of original contact. The experiments indicated that the site of germ tube emergence is determined within 1 min of deposition. This implicated the release of conidial extracellular materials in recognition of the conidium-leaf surface contact site.     

An aggregation index (AI) to quantify spatial patterns of landscapes

There is often need to measure aggregation levels of spatial patterns within a single map class in landscape ecological studies. The contagion index (CI), shape index (SI), and probability of adjacency of the same class (Qi), all have certain limits when measuring aggregation of spatial patterns. We have developed an aggregation index (AI) that is class specific and independent of landscape composition. AI assumes that a class with the highest level of aggregation (AI =1) is comprised of pixels sharing the most possible edges. A class whose pixels share no edges (completely disaggregated) has the lowest level of aggregation (AI =0). AI is similar to SI and Qi, but it calculates aggregation more precisely than the latter two. We have evaluated the performance of AI under varied levels of (1) aggregation, (2) number of patches, (3) spatial resolutions, and (4) real species distribution maps at various spatial scales. AI was able to produce reasonable results under all these circumstances. Since it is class specific, it is more precise than CI, which measures overall landscape aggregation. Thus, AI provides a quantitative basis to correlate the spatial pattern of a class with a specific process. Since AI is a ratio variable, map units do not affect the calculation. It can be compared between classes from the same or different landscapes, or even the same classes from the same landscape under different resolutions.     

Studies on the sorption of organochlorine insecticides by flour stored on or near treated laminated timber or plywood as used in freight containers

Wood preservatives containing a number of organochlorine insecticides, including aldrin, dieldrin, chlordane and lindane, have been approved in Australia for treating timber used as structural components in cargo containers. Studies on the migration of these insecticides from treated laminated timber and plywood, using commercial containers and in the laboratory, are reported here. The highest insecticide residue levels were found in flour samples stored on newly treated laminated sawn timber. Physical pick-up of insecticide from the surface of the floor was considered to be the major source of contamination. Sorption of insecticides from the atmosphere of the container was the most likely source of contamination in samples stored on or near treated plywood.     

Ultrasonographic imaging of the sandhill crane (Grus canadensis) intertarsal joint.

Tendon ossification in the crus and tarsometatarsal regions of cranes makes ultrasonography difficult everywhere except for joints, where ossification is absent. Normal ultrasonographic anatomy of the adult Florida sandhill crane (Grus canadensis pratensis) intertarsal joint is described on the basis of ultrasonography that was performed on the limbs of a cadaver, which were dissected and cross-sectioned subsequently, to correlate ultrasonographic images with anatomic structures. Intertarsal joints of five normal sandhill cranes and two cranes with known intertarsal abnormalities were then imaged bilaterally in transverse and sagittal planes. Ultrasonographic imaging can be used to evaluate the soft-tissue structures on the dorsal and plantar aspects of the intertarsal joint of cranes, and it is a useful adjunct to physical and radiographic examination for localizing injuries to this area.     

The development of Akabane virus-induced congenital abnormalities in cattle

A prospective study of the incidence and severity of congenital deformities of calves, attributable to maternal infection by Akabane virus, was carried out on a population of 174 susceptible animals that were between one and nine months pregnant at the time of infection. The study was carried out in the Hunter Valley of New South Wales during 1983, after an epidemic of Akabane virus infection in late February to early March 1983. The incidence of virus-induced abnormalities in calves and fetuses was 17.8 per cent (31/174). The highest incidence of abnormalities occurred during the third and sixth months of gestation (27 to 29 per cent). The earliest abnormality was observed after infection at 76 days of gestation, and the last after infection at 249 days. The development of the pathological entities of hydranencephaly/porencephaly and arthrogryposis were found to be quite distinct. Cases of hydranencephaly and porencephaly developed after infection between 76 and 104 days of gestation whereas arthrogryposis developed after infection between 103 and 174 days of infection. It was concluded that the type of congenital deformity produced by maternal infection with Akabane virus was dependent on the stage of fetal development at the time of infection. The data suggest that the infection was transplacental and that fetuses of less than two months of age were protected from infection.     

Characterizing 1341 cases of veterinary toxicoses confirmed in western Canada: A 16-year retrospective study

Veterinary toxicoses are frequently observed in western Canada. This study reports the frequency and characteristics of intoxications in animals reported between January 1, 1998 and December 31, 2013. Information was obtained from toxicological case records from the Prairie Diagnostic Services, Saskatoon, Saskatchewan. There were 1341 animal poisonings with 19 compounds over the investigational period. Lead poisoning was the most common toxicity (43.7%). Poisoning with acetylcholinesterase inhibitors and strychnine were also common events. Poisonings were most common in 2001, 2009, and 2012. Intoxications occurred most frequently during the months of May through July. Cattle were the most commonly poisoned species (n = 696), followed by dogs and eagles.